This invention relates to a display unit which has an increment input and a decrement input so as to be controllable to sequentially index through an ordered list of discrete elements and, more particularly, to a control system which provides bidirectional multispeed indexing control of the display unit.
There are numerous display units which require that the user control the display unit to sequentially index through an ordered list of discrete elements. A digital clock is one such type of display unit which requires this type of indexing in order to change the time and/or alarm setting. Another such type of display unit is associated with a computer where the user has to scroll through a list. It would be desirable to have a control system wherein the indexing is controllable to be bidirectional and it would be further desirable to have such a control system wherein the user can control the indexing speed.
According to the present invention, there is provided a bidirectional multispeed indexing control system for a display unit which has an increment input and a decrement input so as to be controllable to sequentially index through an ordered list of discrete elements. The inventive control system includes a first operator actuatable switch, a second operator actuatable switch, and a display control unit. The display unit is responsive to operator actuation of the first and second switches and is effective to provide signals to the increment and decrement inputs of the display unit so as to control the display unit to index through the ordered list in a respective direction according to which of the first and second switches is actuated first. The display control unit is further effective to provide the signals to the increment and decrement inputs of the display unit at a speed which is determined by whether the other of the first and second switches is also actuated.
In accordance with an aspect of this invention, the display control unit is responsive to continued actuation of the other of the first and second switches to increase the indexing speed of the display unit.
In accordance with another aspect of this invention, the display control unit is responsive to subsequent deactuation of the other of the first and second switches to decrease the indexing speed of the display unit.